Monitoring system



Oct. 28, 1947. w. o. SNELLINGvr 2,429,965

' MONITORING SYSTEM f Filed Nov. 9, 1945 ooooodhb //p/ooooeoov 00000000 /f/foooooooo Patented Oct. 28,1947

Walter 0. Snelling, Allentown, Pau, assignor to Trojan Powder Company, Allentown, Pa., a

corporation of New York pplicat'on November 9, 1943, Serial N. 509,637

l' This invention relates to monitoring systems and has for its principal object the provision of a method and apparatus by means of which in carrying out a process consisting of several steps in sequence the doing of each act at the proper time is insured by the givingY of a signal, either audible, visible, or both, when the act is prematurely taken or has not been taken indue season.

It is a further object of this invention to provide a method and apparatus for monitoring, particularlyY suited for control of the several steps in the making of an' explosive. In this field the time at which a certain step should be' taken, such as the opening of. a valve, is dependent upon factors other than time alone, and hence the alarm should beV withheld until after the lapse of a variable amount of time from the first permissible time setting forr that act'.

A further object of the invention is to provide a set ofr paired signals, such as electric lights, onegoverned by a time schedule' and the other governed by the automatic or manual operation of pieces of equipment, such as switches, valves, pumps, etc. By this means a supervisor will know that as long as the lights are paired, either both lit or both out, the system is running properly, but if one light of a pair is lighted alone for an appreciable period of time, it is a signal that a step has not been takenr when it should, or has been taken ahead o'f time', or that some piece of equipment is out of order-a pipe clogged for example. This system which is iirst to be de"- scribed is similar to but a bit simpler than the' preferred system to which alarms have been added as additional Warnings of deviation from the set steps of the process.

As applied specifically to the making of pentaerythritol tetranitrate as one example, there are ten pieces of equipment involved, each connected toy its own electric light on the signal board. When a valve is open and fluid can pass, electricalcontacts on the valve close so that current may pass to the lam-p on the board indicating that the valve is open. This lamp is oneV of a series of signals in a horizontal row onv the control board', one lamp v for' each switch, pump, valve, or other unit which is physically moved during the carrying'v out of the nitration'.. There are thus ten lights in one row and another ten lights immediately above' (or below) this first group of ten lights. The arrangement constitutes', in` effect, an alignment of ten groups of lights, each group' of lights consisting of two lights in spaced relationship. One light of each group indicates an operation that is to be per- 12 Claims.V (Cl. 177-311) l formed, and the second light of such group indicates or marks the performance or doing of that operatiom The control portion of the assembly may be operated by hand but may conveniently consist of a roll of paper containing perforations, like the roll of perforated paper used on a mechanically operated organ or self-playing piano. If preferred, a series of perforated cards, as used in a jacquard loom, may be employed. In both cases, the functions are the same.

In the iirst operation, We will assume' that valves l, 3, and 5 are to be open. Three perforations will be made in the sheet of paper over the drum, corresponding to the three valves that are to be open. The perforated sheet or ribbon is then positioned, ngers pass through the openings i-n the paper and the three lights, l, 3, and 5, are illuminated. When the operator has opened the three corresponding valves, three pairs of lights will be illuminated. At the close or termination of this step, the perforated belt or ribbon is moved forward manually by the operators desire, orV can be moved forward mechanically like clock-work mechanism if this is desired.

In the second position` valve I remains open, valves 3 and 5 should be closed, and valve 8 should be opened. Perforations corresponding to this arrangement would be made in the perforated sheet, as above, and when the corresponding valves have been opened or closed by the operator, the pairs of lights would again be in uniform condition, a light being lighted wherever a valve was open and a light being extinguished' wherever a valve was closed.

It will be noted that the above arrangement not only guides the operator in tellinghim what valves are to be' open and what valves are to be shut at every stage of the operating procedure, but in addition, gives him instant indication at any time that all operating units are not in thev intended or desired position. At all times, when all operating units are in intended or desired posi=tion pairs of lights will either both be lighted,

"' or will. both be extinguished. At any time that a light in the upper row is lighted, Without the corresponding light in the lower row being lighted promptly thereafter, it Will afford positive indication that the desired operating procedure has not been performed.

The present invention, whenY used in connection with a belt or ribbon moved forward by a clockwork mechanism,A will at all times indicate operations that should be performed, and the precise moment at which. such. operations should` be performed. It is possible, however, that through diculties met with in the operation itself a delay may be experienced, and in such case all subsequent steps would be out of sequence. To correct this, the timing mechanism may be arranged to be advanced or retarded, as the case may be, by the operator so as to bring it at any time into step with the actual condition of the cycle. If desired, a separate recording belt or sheet may be so electrically connected as to indicate any such advance or retardation of the control belt or sheet.

It will be evident that this invention also enables a record to be kept at any remote point, showing all changes in all Valves, pumps, motors, etc., used or employed in the chemical manufacturing process. In the case of a mono nitrator, for example, a recording mechanism in the con. trol oce would automatically show the moment at which all valves were opened and were shut, and if desired, parallel pens operated by the valve circuits and the perforated sheet circuits would indicate both the precise moment at which each operation should be performed, and the actual moment at which it was performed.

Figure 1 is a diagram showing the system in a simple form.

Figure 2 shows a more complete system.

Figure 3 shows the control board.

Figure 4 illustrates a modified thermostat.

Figure 5 shows a modified circuit.

In the simple form shown in Figure 1 switch I0 has been thrown to the left closing a circuit from line Il through wires l2, I4, and I5. This causes lamp I6 to light, indicating that the corresponding step in the process should be taken. Light Il, indicating when lit that this step has been taken, is paired with light I6 on a control board I8 containing as many pairs oi lights as there are steps in the process, ten for example, and there are as many boards as there are stations at which the processes are carried out.

If for any reason the attendant at the station fails to `perform the appropriate act the bimetallic thermostatic strip 2E! is heated by lamp iii so that it bends until it touches the adjustable post 2|. This completes a circuit Il, I2, ill, 2|, 20, 22, 23, thru switch 25, and wires 26 and 21 to coil 28 which operates the buzzer 30 sounding an alarm or lighting a warning light 29, or both. This will indicate to the attendant or the supervisor or both that the proper step has not been taken. The supervisor has previously been notied by the fact that the lights of the pair are neither both on nor both off as would be the case if the process were being performed properly.

Should the attendant have taken the step promptly, by throwing switch 25 to the right, thus energizing the relay 3! to the valve or other piece ofY equipment to be operated, he would have broken the circuit between wires 23 and 26 and the buzzer 36 would not operate or if already in operation would cease. This throwing of the attendants switch 25 would cause the light I1 to burn and this would make it similar to the paired light I6 indicating that all was well. The thermostat 35 would in time contact its post 36, as in Figure 2, but wire 37 to switch l0 is now open at that point so the buzzer would not be operated.

Later, at the time this step of the process should be finished, the switch l is thrown to the right, putting out the light I6, operating the buzzer 30 until the switch 25 is thrown to deenergize relay 3l and put out the light Il'. The circuit is II--I2-25-3l-lT-l5, and also Il 4 |2-25--3l-I0-31-36--35-26--21--28- l5. The thermostatic strip 35 cools and finally breaks the buzzer circuit. The perforations in the control ribbon or roll allow for the appropriate time lag.

In similar manner, should the attendant take a step ahead of time, he would light lamp l1 and after the number of seconds allowed by the adjustment of post 3%, the buzzer would sound. Also the burning of light l1 paired with the unlighted lamp I6 on the board would indicate that the step was not called for (light i 6 being out) but it had been taken, as lamp bulb il was illuminated.

The diagram of Figure 2 shows the circuits iirst used for the process. Stops 2l and 36 are threaded so that the time lag may be adjusted from a single second to as much as an entire minute. Switches i0 and lli ordinarily have their knives up but by moving the knife to lower position the thermostat post is connected to the thermostat blade, thus cancelling the time lag. With the knives up, the circuits are as before, but when the knives are down they short-circuit the thermostats so that the alarm sounds immediately upon switch l0 being thrown to the left when the switch 25 is at the left, for example; the circuits then being ll-lZ-lD-l-lE-l and Il-i-lii-I-li-25-fil-2l-28|5.

In Figure 4 the lamps I6 and il are placed adjacent a mercury U-tube having an air bulb 4l at the top of each leg i12. A wire i3 extends into both legs above the normal level of the mercury and a wire 44 is fused through the bottom of the tube so as to be in constant contact with the mercury. These wires are connected into the circuit in the place of the wires from the thermostat and its post and operate similarly. That is, should either lamp be lighted alone the air in the adjacent bulb lll would expand suiiiciently to force the mercury into contact with the wire 133 on the opposite side, thus completing the alarm circuit. The time lag here is altered for the different steps by using electric light bulbs of different heating rates or wattage.

In the modification shown in Figure 5 the coils 60 and 6l are in series with the lights i6 and il respectively, the circuits for which are as previously described. When either of these lamps is lighted current passes through its coil GB or 6l, attracting armature 63 and causing a flow of current through solenoid (or relay) 64, attracting the armature 55. This tilts the mercury U-tube to the right about pivot @6 but current cannot pass between the contacts 61 and i3 until after the elapsing of enough time for the mercury to flow through the restricted opening 59. The time is adjusted by the screw 56, which when advanced moves armature l5 about its pivot M, bringing the mercury level nearer to the two contacts 4l and 138. When the mercury touches the two contacts the bell or other alarm circuit is completed, il to spring 5l to stop 52, which lies in the path of the anchored end of spring 5l and only engages it when the U-tube is in Ibell ringing position, and then to bell 53. Should both lights be lighted the coils Si! and 6l are neutralized and the switch $3 is not attracted.

'It will of course be evident that whereas in this specication I have stated that the signal light connected to a valve was so arranged as to be lighted when the valve was open, and the light was unlighted when the valve was in a closed position, the invention would still be applicable if this arrangement were reversed, providing that the signal equipment also sent its signals in re- Verse order.

The invention relates to the use of light in pair relationship, but the signicance of any light being lighted or being unlighted is not an essential part of the invention, and may be varied at will, providing the relationship of the associated pair of lights is similarly varied. For the convenience of the operator, I prefer to have all valves so wired that the signal light associated with such valves is lighted when the Valve is open so that fluid may pass there-through, and the light is unlit when the valve is so turned that now of fluid through it is interrupted.

If so desired, colored signal lights may be used, a given color being assigned to a given operation or group of operations.

What I claim is: y

1. The method of insuring adherence to a planned sequence of steps which consists in arranging signals in pairs corresponding to the steps of the system to be followed, operating one signal of each pair when that step should be taken, operating the other signal of that pair when the step is taken, and operating an alarm if either of the signals is operated more than a chosen interval of time before the other signal of that pair, whereby to indicate either that the step was not taken on time or was prematurely taken.

2. The method of insuring adherence to a planned sequence of steps which consists in arranging electrical light signals in sets corresponding to the steps of the system to be followed, Ioperating one signal of each set when that step should be taken, operating another signal of that pair when the step is taken, and initiating a delayed action mechanism when one light burns alone to sound an alarm, whereby the sounding of the alarm will indicate either that the step was not taken on time or was prematurely taken.

3. In a monitoring system covering the operation in sequence of a plurality of devices such as valves, switches, pumps, etc.: a signal arranged Vfor simultaneous operation with one of the devices, a second signal paired with the first mentioned signal, means arranged for automatic operation of said second signal when the device should be operated, an alarm, means arranged for operation of said alarm when either signal of the pair operates alone, a delayed action mechanism for withholding the alarm for a chosen period of time, and means for rendering the alarm inoperative when both signals are operated.

4. The device of claim 3 in which the devices are manually operated and the delayed action mechanism is adjustable for various periods of time whereby the alarm for one device will be operated in less time than the alarm for another of the devices, whereby to allow for manual control subject to other factors than time alone.

5. The device of claim 3 in which the delayed action mechanism includes a mercury U-tube having a restricted opening for passage of the mercury from leg to leg.

6. The device of claim 3 in which the delayed action mechanism includes a mercury U-tube having a restricted opening for passage of the mercury from leg to leg, and means for adjusting the time lag caused by the restricted opening.

7. In a monitoring system for insuring adherence to a planned taking of steps involving the operation in sequence of a plurality of manually operated devices; a relay for one of the devices, a rst switch circuit forenergizing said relay, a first lamp in said circuit indicating when lit that the step has been taken, a second switch circuit including a second lamp in proximity to said first lamp and forming therewith a pair, said second lamp when lit indicating that the step should be taken, whereby when only one lamp of a pair is lit it will indicate that the step was not taken in time or was prematurely taken, an electrical alarm, and means for energizing said alarm a period of time after lighting either lamp without the other.

8. In a monitoring system for insuring close observance with a time schedule of performing a series of steps in a process wherein the time of performing the full cycle is of less importance than the times for performing each of the several steps of the cycle, as for example, in a process for making an explosive where valves should be opened and closed and motors started and stopped in denitely timed relationship; a time schedule signal, a performance signal paired with said signal for ready comparison therewith, a Warning device, means for energizing the time schedule signal when a step of said process should be taken and for deenergizing that signal when step is completed, and delayed action means responsive to either signal for energizing the warning device whenever one signal is energized and the other signal is not energized after a predetermined time, thus signalling'that the step is prematurely taken or is delayed.

9. The system of claim 8 in which the time schedule signal and the performance signal are two closely spaced electric lights, and the warning device is an audible alarm.

10. The device of claim 8 in which the delayed action means includes bimetallic thermostats and the signals are positioned adjacent said means and operate same.

11. The device of claim 8 in which the delayed action means includes bimetallic thermostats and the signals are positioned adjacent said means and operate same and each of the thermostats is independently adjustable whereby a different time lag may be set for each signal.

12. rIfhe device pf claim 3 in which a two-way switch is interposed between one signal and the alarm so that reversing the switch will render the delayed action mechanism inoperative so that the alarm is given immediately upon the operation of said one signal when the other signal is not in operation.

' WALTECRI O. SNELLING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 754,496 Potter Mar. l5, 1904k 1,108,998 Levison Sept. 1, 1914 1,575,599 Hornberger Mar. 2, 1926 1,600,753 Boardman Sept, 21, 1926 1,999,810 Hershey Apr. 30, 1935 2,279,121 Kistler Apr. 7, 1942 1,614,257 Scheler Jan. 11, 1927 1,743,741 Warren Jan. 14, 1930 1,888,486 Boedtcher Nov. 22, 1932 2,389,204 Ludi et al Nov. 20, 1945 

